"Further delays are likely as the Commercial Crew Program's schedule risk analysis shows that the certification milestone is likely to slip. The analysis identifies a range for each contractor, with an earliest and latest possible completion date, as well as an average. The average certification date was December 2019 for Boeing and January 2020 for SpaceX, according to the program's April 2018 analysis. Since the Space Shuttle was retired in 2011, the United States has been relying on Russia to carry astronauts to and from the International Space Station (ISS). Additional delays could result in a gap in U.S. access to the space station as NASA has contracted for seats on the Russian Soyuz spacecraft only through November 2019.

NASA is considering potential options, but it does not have a contingency plan for ensuring uninterrupted U.S. access. NASA's certification process addresses the safety of the contractors' crew transportation systems through several mechanisms, but there are factors that complicate the process. One of these factors is the loss of crew metric that was put in place to capture the probability of death or ...